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German National Committee of ICID (GECID).
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German National Committee of ICID (GECID) Possibilities of using the drip irrigation laterals on centre pivot irrigation machinesJano Anter, Dr. Heinz Sourell, Hans-Heinrich Thörmann, Federal Research Institute for Rural Areas, Forestry and Fisheries, GermanyInstitute of Agricultural Technology and Biosystems Engineering 27 June 2012, Adelaide
Contents • Irrigation in Germany • Advantages & disadvantages of drip irrigation and center • pivot • Steps to mobile drip irrigation • Technical aspects • Costs analysis • Summary
Irrigation in Germany • 3% oftheagriculturallandareirrigated in Germany • Humid climate, dry periods, sandysoils • Culturesworthofirrigation: i.e. Potatos, Sugar beets • Useof modern irrigationtechniques • The techniquesaredeveloped in termsofclaimsbyfarmers: - Waterdistrubtion - Intensityoflabour - Water-efficient - Energyconsumption
Advantages & disadvantages of drip irrigation • + • High water use efficiency • Low water losses • Low energy requirements • Possibility of chemigation • - • High total costs • High labour requirements for the assembly and disassembly
+ Full-Automaticmachinemanagement Low labourrequirements Moderate capitalrequirement Simple touse - Waterlosses Wind drift High energyrequirements Advantages & disadvantages of center pivot with sprinkler
Operating costs Drip Irrigation Center Pivot
Center pivot Drip irrigation Mobile Drip Irrigation Steps to mobile drip irrigation
Field experiments • The Center pivotconsisting 9 towers • The total lenghtofthispivotmachine was approximately 428 m • The total irrigatedareaofabout 57 ha • Driptubesdistance: 0.75 m • In thefieldinvestigations, twooperatingpressureswereusedattheinletofthedriptubes (50 kPaand 100 kPa)
Emitters Mobile dripirrigationneedsemittersthathave: • High discharge(8 l/h & 10 l/h) • Low distancebetweenthem(0.15 m) Toreducethelenghtofdriptubesandthenumbersofemitters • High emissionuniformity(over 95 %) • Low coefficientofvariation(lowerthan 5 %) Toenhanceirrigationwaterdistrubtion on thesoilsurface
Length of drip tubes at two pressures • The lenghtofthedriptubesisdependent upon theemitterdischarge • andthedistancefromthepivotpoint • The lenghtofthedriptubesincreasesasthedistancefromthepivot • pointgrows • Forthestabilityofthecentrepivotirrigator, additional frictionforceis • important • The frictionforceat 50 kPawerehigherthanthefrictionforceat 100 kPa (2470 N & 1743 N attheninthtower) • This forceissuitablefortheelectricmotorswhicharemounted on eachtower.
Summary • High water efficiency / Water saving up to 20% • Energy conservation up to 40% • The total costs of MDI were close to the total costs of a CP • For the same area we need only 1,6 % respectively of the tubes that would needed for a SDI • Filtering of the water can become important • Further experiments with other plants is necessary